1. Field of the Invention
The present invention relates to a semiconductor device. More particularly, the present invention relates to a semiconductor device including a plurality of semiconductor chips which are connected to each other through a bus having a larger width (i.e., having a number of buses) such as an address bus.
2. Description of the Related Art
Recently, a now field of technology called xe2x80x9cmulti-mediaxe2x80x9d has be en developed. The important features of this technology includes its processing of dynamic images. In order to process the dynamic images, a huge amount of data must be transferred at a high speed. In order to satisfy this requirement, the width of a data bus for transferring the data has been often increased.
However, such an increase in width of the data bus leads to an increase in size of the semiconductor device. Therefore, a technique of suppressing the increase in size of the semiconductor device by sharing a data bus and an address bus has been developed.
However, such a conventional technique merely shares the data bus and the address bus, and cannot reduce the width of the data bus itself (or the address bus itself).
According to one aspect of the present invention, a semiconductor device includes a transmitting section; and a receiving section, wherein the transmitting section and the receiving section are connected to each other through a bus, the transmitting section includes an encoding section for encoding data including a plurality of bits to produce bit-position information which indicates a position of at least one bit selected from the plurality of bits included in the data, and an output section for outputting the bit-position information onto the bus, and the receiving section includes an input section for receiving the bit-position information from the bus, and a decoding section for decoding the bit-position information to produce the data.
In one example, the at least one bit is a bit having a specific logic value.
In one example, the at least one bit is a bit having a different logic value from a logic value of a corresponding bit of previous data.
In one example, the transmitting section further includes a bit-number comparison information producing section for producing bit-number comparison information indicating whether or not a number of bits having the specific logic value is larger than a number of bits having a logic value other than the specific logic value in the plurality of bits included in the data, the output section outputs the bit-position information and the bit-number comparison information onto the bus, the input section receives the bit-position information and the bit-number comparison information from the bus, and the decoding section decodes the bit-position information based on the bit-number comparison information to produce the data.
In one example, the encoding section encodes the data to produce a plurality of pieces of bit-position information, and the output section serially outputs the plurality of pieces of bit-position information onto the bus.
According to another aspect of the present invention, a semiconductor device connected to a bus includes an encoding section for encoding data including a plurality of bits to produce bit-position information which indicates a position of at least one bit, selected from the plurality of bits included in the data; and an output section for outputting the bit-position information onto the bus.
According to still another aspect of the present invention, a semiconductor device connected to a bus includes: an input section for receiving, from the bus, bit-position information which indicates a position of at least one bit selected from a plurality of bits included in data; and a decoding section for decoding the bit-position information to produce the data.
Hereinafter, functions of the present invention will be described.
According to a semiconductor device of the present invention, bit-position information, which indicates a position of at least one bit selected from a plurality of bits contained in the data, is produced, and the bit-position information is transmitted. Therefore, by using the bit-position information having a number of bits less than the number of bits of the data to be transferred, the content of the data is transmitted from a transmitting section to a receiving section. Thus, a bit width of a bus connecting the transmitting section with the receiving section can be made smaller than that of the data to be transmitted. For example, 8-bit data can be transmitted by using a 3-bit bus. As a result, the size of the semiconductor device can be reduced.
Thus, the invention described herein makes possible the advantage of providing a semiconductor device including a plurality of semiconductor chips which are connected to each other through a bus having a smaller width.